I use a hard drive tray, slickest addition ever. Today I bumped the pc case slightly (with something soft, not hard) and ... no problems, booted up and ran fine (2 hrs). Later mouse freezes. Couldn't get task manager (no keyboard?) so powered off. Upon reboot: no post beep (normal), no video, leds for hard drive light as does mouse so I can see it's going thru POST. Really doubt its any malware as I use Sandboxie & find it pretty ironclad, and I was reading on a safe site. Tried another HDD (different OS) - same. Tried connecting using internal SATA cables - same. Tried a live CD (DVD) of Linux Mint and everything works BUT this is running off the disc, not the HDD in the tray. Can view the HDD in Mint. BIOS is Award "F2" ver. I haven't bothered to update (6/09). Wondering why anyone would create a BIOS w/o beep. I find no setting in my bios config allowing you to turn that on/off. Doesn't seem to be an issue. Q - as everything works in Mint I fail to see how it could be the HDD connection via the tray (SATA) or from the internal SATA cables. So system recognizes HDD is present or else it would beep. Obviously not the mobo, ram, PSU, etc. because pc boots and runs fine off the Live disc. I don't think it's something intermittent but can't rule that out. Will try re-seating SATA cables including for the drive tray. Any ideas if I can't get a HDD to boot? Have not changed any hardware or software. System: Phenom II X2 550 black (no oc) on a GB GA-MA785GM-US2H, 2 GB Geil black dragon ram and a Corsair 400 watt. Has been fine.